// Tencent is pleased to support the open source community by making RapidJSON available.
//
// Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip. All rights reserved.
//
// Licensed under the MIT License (the "License"); you may not use this file except
// in compliance with the License. You may obtain a copy of the License at
//
// http://opensource.org/licenses/MIT
//
// Unless required by applicable law or agreed to in writing, software distributed
// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
// CONDITIONS OF ANY KIND, either express or implied. See the License for the
// specific language governing permissions and limitations under the License.

#ifndef RAPIDJSON_ITOA_
#define RAPIDJSON_ITOA_

#include "../rapidjson.h"

RAPIDJSON_NAMESPACE_BEGIN
namespace internal {

inline const char* GetDigitsLut() {
	static const char cDigitsLut[200] = {
		'0', '0', '0', '1', '0', '2', '0', '3', '0', '4', '0', '5', '0', '6', '0', '7', '0', '8', '0', '9',
		'1', '0', '1', '1', '1', '2', '1', '3', '1', '4', '1', '5', '1', '6', '1', '7', '1', '8', '1', '9',
		'2', '0', '2', '1', '2', '2', '2', '3', '2', '4', '2', '5', '2', '6', '2', '7', '2', '8', '2', '9',
		'3', '0', '3', '1', '3', '2', '3', '3', '3', '4', '3', '5', '3', '6', '3', '7', '3', '8', '3', '9',
		'4', '0', '4', '1', '4', '2', '4', '3', '4', '4', '4', '5', '4', '6', '4', '7', '4', '8', '4', '9',
		'5', '0', '5', '1', '5', '2', '5', '3', '5', '4', '5', '5', '5', '6', '5', '7', '5', '8', '5', '9',
		'6', '0', '6', '1', '6', '2', '6', '3', '6', '4', '6', '5', '6', '6', '6', '7', '6', '8', '6', '9',
		'7', '0', '7', '1', '7', '2', '7', '3', '7', '4', '7', '5', '7', '6', '7', '7', '7', '8', '7', '9',
		'8', '0', '8', '1', '8', '2', '8', '3', '8', '4', '8', '5', '8', '6', '8', '7', '8', '8', '8', '9',
		'9', '0', '9', '1', '9', '2', '9', '3', '9', '4', '9', '5', '9', '6', '9', '7', '9', '8', '9', '9'
	};
	return cDigitsLut;
}

inline char* u32toa(uint32_t value, char* buffer) {
	const char* cDigitsLut = GetDigitsLut();

	if (value < 10000) {
		const uint32_t d1 = (value / 100) << 1;
		const uint32_t d2 = (value % 100) << 1;

		if (value >= 1000)
			*buffer++ = cDigitsLut[d1];
		if (value >= 100)
			*buffer++ = cDigitsLut[d1 + 1];
		if (value >= 10)
			*buffer++ = cDigitsLut[d2];
		*buffer++ = cDigitsLut[d2 + 1];
	} else if (value < 100000000) {
		// value = bbbbcccc
		const uint32_t b = value / 10000;
		const uint32_t c = value % 10000;

		const uint32_t d1 = (b / 100) << 1;
		const uint32_t d2 = (b % 100) << 1;

		const uint32_t d3 = (c / 100) << 1;
		const uint32_t d4 = (c % 100) << 1;

		if (value >= 10000000)
			*buffer++ = cDigitsLut[d1];
		if (value >= 1000000)
			*buffer++ = cDigitsLut[d1 + 1];
		if (value >= 100000)
			*buffer++ = cDigitsLut[d2];
		*buffer++ = cDigitsLut[d2 + 1];

		*buffer++ = cDigitsLut[d3];
		*buffer++ = cDigitsLut[d3 + 1];
		*buffer++ = cDigitsLut[d4];
		*buffer++ = cDigitsLut[d4 + 1];
	} else {
		// value = aabbbbcccc in decimal

		const uint32_t a = value / 100000000; // 1 to 42
		value %= 100000000;

		if (a >= 10) {
			const unsigned i = a << 1;
			*buffer++ = cDigitsLut[i];
			*buffer++ = cDigitsLut[i + 1];
		} else
			*buffer++ = static_cast<char>('0' + static_cast<char>(a));

		const uint32_t b = value / 10000; // 0 to 9999
		const uint32_t c = value % 10000; // 0 to 9999

		const uint32_t d1 = (b / 100) << 1;
		const uint32_t d2 = (b % 100) << 1;

		const uint32_t d3 = (c / 100) << 1;
		const uint32_t d4 = (c % 100) << 1;

		*buffer++ = cDigitsLut[d1];
		*buffer++ = cDigitsLut[d1 + 1];
		*buffer++ = cDigitsLut[d2];
		*buffer++ = cDigitsLut[d2 + 1];
		*buffer++ = cDigitsLut[d3];
		*buffer++ = cDigitsLut[d3 + 1];
		*buffer++ = cDigitsLut[d4];
		*buffer++ = cDigitsLut[d4 + 1];
	}
	return buffer;
}

inline char* i32toa(int32_t value, char* buffer) {
	uint32_t u = static_cast<uint32_t>(value);
	if (value < 0) {
		*buffer++ = '-';
		u = ~u + 1;
	}

	return u32toa(u, buffer);
}

inline char* u64toa(uint64_t value, char* buffer) {
	const char* cDigitsLut = GetDigitsLut();
	const uint64_t kTen8 = 100000000;
	const uint64_t kTen9 = kTen8 * 10;
	const uint64_t kTen10 = kTen8 * 100;
	const uint64_t kTen11 = kTen8 * 1000;
	const uint64_t kTen12 = kTen8 * 10000;
	const uint64_t kTen13 = kTen8 * 100000;
	const uint64_t kTen14 = kTen8 * 1000000;
	const uint64_t kTen15 = kTen8 * 10000000;
	const uint64_t kTen16 = kTen8 * kTen8;

	if (value < kTen8) {
		uint32_t v = static_cast<uint32_t>(value);
		if (v < 10000) {
			const uint32_t d1 = (v / 100) << 1;
			const uint32_t d2 = (v % 100) << 1;

			if (v >= 1000)
				*buffer++ = cDigitsLut[d1];
			if (v >= 100)
				*buffer++ = cDigitsLut[d1 + 1];
			if (v >= 10)
				*buffer++ = cDigitsLut[d2];
			*buffer++ = cDigitsLut[d2 + 1];
		} else {
			// value = bbbbcccc
			const uint32_t b = v / 10000;
			const uint32_t c = v % 10000;

			const uint32_t d1 = (b / 100) << 1;
			const uint32_t d2 = (b % 100) << 1;

			const uint32_t d3 = (c / 100) << 1;
			const uint32_t d4 = (c % 100) << 1;

			if (value >= 10000000)
				*buffer++ = cDigitsLut[d1];
			if (value >= 1000000)
				*buffer++ = cDigitsLut[d1 + 1];
			if (value >= 100000)
				*buffer++ = cDigitsLut[d2];
			*buffer++ = cDigitsLut[d2 + 1];

			*buffer++ = cDigitsLut[d3];
			*buffer++ = cDigitsLut[d3 + 1];
			*buffer++ = cDigitsLut[d4];
			*buffer++ = cDigitsLut[d4 + 1];
		}
	} else if (value < kTen16) {
		const uint32_t v0 = static_cast<uint32_t>(value / kTen8);
		const uint32_t v1 = static_cast<uint32_t>(value % kTen8);

		const uint32_t b0 = v0 / 10000;
		const uint32_t c0 = v0 % 10000;

		const uint32_t d1 = (b0 / 100) << 1;
		const uint32_t d2 = (b0 % 100) << 1;

		const uint32_t d3 = (c0 / 100) << 1;
		const uint32_t d4 = (c0 % 100) << 1;

		const uint32_t b1 = v1 / 10000;
		const uint32_t c1 = v1 % 10000;

		const uint32_t d5 = (b1 / 100) << 1;
		const uint32_t d6 = (b1 % 100) << 1;

		const uint32_t d7 = (c1 / 100) << 1;
		const uint32_t d8 = (c1 % 100) << 1;

		if (value >= kTen15)
			*buffer++ = cDigitsLut[d1];
		if (value >= kTen14)
			*buffer++ = cDigitsLut[d1 + 1];
		if (value >= kTen13)
			*buffer++ = cDigitsLut[d2];
		if (value >= kTen12)
			*buffer++ = cDigitsLut[d2 + 1];
		if (value >= kTen11)
			*buffer++ = cDigitsLut[d3];
		if (value >= kTen10)
			*buffer++ = cDigitsLut[d3 + 1];
		if (value >= kTen9)
			*buffer++ = cDigitsLut[d4];
		if (value >= kTen8)
			*buffer++ = cDigitsLut[d4 + 1];

		*buffer++ = cDigitsLut[d5];
		*buffer++ = cDigitsLut[d5 + 1];
		*buffer++ = cDigitsLut[d6];
		*buffer++ = cDigitsLut[d6 + 1];
		*buffer++ = cDigitsLut[d7];
		*buffer++ = cDigitsLut[d7 + 1];
		*buffer++ = cDigitsLut[d8];
		*buffer++ = cDigitsLut[d8 + 1];
	} else {
		const uint32_t a = static_cast<uint32_t>(value / kTen16); // 1 to 1844
		value %= kTen16;

		if (a < 10)
			*buffer++ = static_cast<char>('0' + static_cast<char>(a));
		else if (a < 100) {
			const uint32_t i = a << 1;
			*buffer++ = cDigitsLut[i];
			*buffer++ = cDigitsLut[i + 1];
		} else if (a < 1000) {
			*buffer++ = static_cast<char>('0' + static_cast<char>(a / 100));

			const uint32_t i = (a % 100) << 1;
			*buffer++ = cDigitsLut[i];
			*buffer++ = cDigitsLut[i + 1];
		} else {
			const uint32_t i = (a / 100) << 1;
			const uint32_t j = (a % 100) << 1;
			*buffer++ = cDigitsLut[i];
			*buffer++ = cDigitsLut[i + 1];
			*buffer++ = cDigitsLut[j];
			*buffer++ = cDigitsLut[j + 1];
		}

		const uint32_t v0 = static_cast<uint32_t>(value / kTen8);
		const uint32_t v1 = static_cast<uint32_t>(value % kTen8);

		const uint32_t b0 = v0 / 10000;
		const uint32_t c0 = v0 % 10000;

		const uint32_t d1 = (b0 / 100) << 1;
		const uint32_t d2 = (b0 % 100) << 1;

		const uint32_t d3 = (c0 / 100) << 1;
		const uint32_t d4 = (c0 % 100) << 1;

		const uint32_t b1 = v1 / 10000;
		const uint32_t c1 = v1 % 10000;

		const uint32_t d5 = (b1 / 100) << 1;
		const uint32_t d6 = (b1 % 100) << 1;

		const uint32_t d7 = (c1 / 100) << 1;
		const uint32_t d8 = (c1 % 100) << 1;

		*buffer++ = cDigitsLut[d1];
		*buffer++ = cDigitsLut[d1 + 1];
		*buffer++ = cDigitsLut[d2];
		*buffer++ = cDigitsLut[d2 + 1];
		*buffer++ = cDigitsLut[d3];
		*buffer++ = cDigitsLut[d3 + 1];
		*buffer++ = cDigitsLut[d4];
		*buffer++ = cDigitsLut[d4 + 1];
		*buffer++ = cDigitsLut[d5];
		*buffer++ = cDigitsLut[d5 + 1];
		*buffer++ = cDigitsLut[d6];
		*buffer++ = cDigitsLut[d6 + 1];
		*buffer++ = cDigitsLut[d7];
		*buffer++ = cDigitsLut[d7 + 1];
		*buffer++ = cDigitsLut[d8];
		*buffer++ = cDigitsLut[d8 + 1];
	}

	return buffer;
}

inline char* i64toa(int64_t value, char* buffer) {
	uint64_t u = static_cast<uint64_t>(value);
	if (value < 0) {
		*buffer++ = '-';
		u = ~u + 1;
	}

	return u64toa(u, buffer);
}

} // namespace internal
RAPIDJSON_NAMESPACE_END

#endif // RAPIDJSON_ITOA_
